As a first example of a battery apparatus having such structure, a battery apparatus having, for example, the structure shown in FIG. 8 has been conventionally known. A battery apparatus 1 shown in FIG. 8 includes a battery unit 2 having a power-generating element, a battery storage 3 having a storage portion 5 in which the battery unit 2 is stored, and a lid 4 to close the storage portion 5 of the battery storage 3.
The battery apparatus 1 is used, for example, as a power source for a mobile phone unit, and the battery unit 2 has an arched-shape due to the limitation of the space to be stored in the mobile phone unit. As the battery unit 2, for example, polymer secondary cell is employed. The battery storage 3 for storing the battery unit 2, and the lid 4 are formed of synthetic resin such as polycarbonate (PC).
On the periphery of the battery storage 3 surrounding the storage portion 5, a step portion is circumferentially provided. On the other hand, a corresponding step portion engaged with that step portion of the battery storage 3 is provided on the periphery of the lid 4. By engaging the step portion of the lid 4 with that of the battery storage 3, the positions of the battery storage 3 and the lid 4 are determined to each other and the battery storage 3 and lid 4 are overlapped in a predetermined state. Contacting portions of the battery storage 3 and the lid 4 are joined, for example, by bonding means such as ultrasonic deposition, and the battery storage 3 and the lid 4 are connected to be integrally formed.
Two electrode terminals 2a, 2b are lead out from the battery unit 2 and are connected to a circuit substrate 6a of a control circuit 6 provided for controlling discharge, charge, and so on of the battery unit 2. To the circuit substrate 6a, there are connected a pair of terminals 3a, 3b provided on the battery storage 3, through which the circuit substrate is connected to the outside. Numeral 7 denotes an insulating board functioning as a partition to separate the battery unit 2 and the controlling circuit 6. Further, numeral 8a denotes double-faced tape for fixing the battery unit 2 in the lid 4, and numeral 8b denotes a double-faced tape for fixing the battery unit 2 in the battery storage 3.
However, with respect to the conventional battery apparatus 1 having such structure, since the battery storage 3 and the lid 4 are both formed of synthetic resin, it is difficult to meet the demand of providing a thinner battery storage 3 and lid 4, and therefore there was a problem in which capacity of the power-generating element can not be increased in the case where the outside dimensions are unchanged.
For example, with respect to a mobile phone unit, while a smaller unit body is strongly requested, such demand as to be able to use the unit as long as possible has been extremely great. Therefore, there is a strong desire to obtain a mobile phone unit in which only the capacity of a power-generating element is made to be large enough to discharge for a long period of time without changing the outside dimensions of the battery apparatus 1.
However, in the above-mentioned battery apparatus 1, since the battery storage 3 and the lid 4 are both formed of synthetic resin that has problems in pliability, strength, and the like, it is difficult to reduce the thickness of the battery storage 3 and the lid 4.
In order to solve the above problems, as shown in FIG. 9, there has been provided a battery apparatus 10 with an improved structure. In the battery apparatus 10, only a battery storage 11 and a lid 12 are improved and no other constituents are modified. Accordingly, hereupon only the battery storage 11 and the lid 12 will be explained, and to other constituents the same numerals are given and the explanation thereof is omitted.
The battery storage 11 of the battery apparatus 10 is composed of a frame 13 in which a large square opening 11a is provided on the lower surface portion thereof and a closing unit 14 which is integrally provided with the frame 13 to close the opening 11a. Similarly, the lid 12 is composed of a frame 15 in which a large square opening 12a is provided on the upper surface portion thereof and a closing unit 16 which is integrally provided with the frame 15 to close the opening 12a. While the frames 13 and 15 are formed of synthetic resin, the closing units 14 and 16 are formed of metal, and by employing what is called insert molding the frames and closing units are integrally formed.
Further, in FIG. 9, a numeral 9a denotes a double-face tape also functioning as an insulating tape provided between the battery unit 2 and the lid 12. Further, a numeral 9b denotes a double-face tape also functioning as an insulating tape provided between the battery unit 2 and the battery storage 11.
According to the battery apparatus 10 which includes the battery storage 11 and the lid 12 having such structure, if the outside dimensions are identical and each member has the same strength, members formed of metal can be made extremely thinner compared to those formed of synthetic resin. Accordingly, with respect to the battery storage 11 and the lid 12, a capacity of the storage portion 5 can be made larger to the amount of decrease in the thickness of the closing units 14 and 16 which are formed of metal. Consequently, the thickness of the battery unit 2 can increase as much as the capacity of the storage portion 5 increases, thereby increasing the capacity of the battery unit 2 to obtain a larger amount of electricity.
However, in the above-mentioned improved battery apparatus 10, since the insert molding is required to fabricate both the battery storage 11 and the lid 12, it is necessary to prepare a molding die having a complicated structure, which causes problems of increasing production cost and requiring much time and work in a production process.
The present invention is made in light of the above problems and provides a battery apparatus, in which a lid that closes the end of an opening of a storage portion of a battery storage, or a closing unit that closes the bottom of the battery storage is formed to be capable of being engaged with the battery storage; means for fixing the lid to the battery storage or for fixing the closing unit to the lid is provided to firmly fix the lid to the battery storage, or to firmly fix the closing unit to the lid to be integrally formed, respectively, preventing each member from being separated; and a capacity of the storage portion is made as large as possible to increase the capacity of the battery unit and thus increase the amount of electricity.